// 函数组合演示
function compose (f,g){
  return function(value){
    return f(g(value))
  }
}

function rever(array){
  return array.reverse()
}

function first(array){
  return array[0]
}

const fn=compose(first, rever)

const arr=[1,2,3,4,5]
console.log(fn(arr));
